This is an open-label, noncomparative, add-on therapy, extension study in patients who have previously participated in a tiagabine HCL epilepsy study. However, during the course of the study concomitant AEDs may be gradually withdrawn so that some patients may be expected to acheive tiagabine HCL monotherapy. This study may be conducted at any site that is conducting or has conducted, tiagabine HCL clinical studies in the United States. THe objective of this study is to determine the safety of tiagabine HCl as chronic therapy for epilepsy.